Here's the deal. (Destiny)

Each gold frame costs 1 Ballistics Log to buy. So, this week, you could only have done two of them (unless you saved a completed Weekly Bounty from last week).

That's what I experienced on other weeks, but this week I was only offered the chance to buy 1 gold frame. This is with no weapon frames and one Ballistics Log in my inventory.

I'm still unclear what exactly happens, but there is a glitch that can cause frames to disappear. If you have a frame that requires a Gofannon Forge complete in your inventory when you complete a frame in the Volundr Forge, the Gofannon frame will disappear from your inventory, and it will disappear from ADA-1's inventory as well. However, you can only buy one frame from ADA-1 at a time, so I don't know how folks are getting multiple frames in the first place.

EDIT: Regarding which drops will be Powerful: I guess I haven't paid enough attention, but I was under the assumption that the gold weapon frames would be Powerful drops the first time you complete them for the week. If you spend a Ballistics Log to buy it, it will be Powerful, if you spend Modulus Reports, it will be a normal drop. ADA-1 also has a weekly challenge for completing 2 Powerful Frames, which I think is supposed to give you Black Armory armor, but I don't know if that's Powerful or not (I assume it would be).

Yeah, all my gold frames have been powerful. I forgot about that challenge, so that's at least where some PG is coming from. I could have sworn I got even more unexpected high level Black Armory weapons from completing forges, though. I definitely got an AR this week even though I didn't complete or have the weapon frame.